removeFirst method
Removes and returns the first element of this queue.
The queue must not be empty when this method is called.
Implementation
@override
E removeFirst() => apply(removeFirst, null).values.first.first;
removeFirst method
Removes and returns the first element of this queue.
The queue must not be empty when this method is called.
@override
E removeFirst() => apply(removeFirst, null).values.first.first;